It's derived from realism in that it's a stylized representation of what we see in real life. It breaks a few rules to accommodate this stylization which is what results in the unique visual appearance of anime. However, one must first know the rules in order to break them, and the study of realism will lay a sound foundation from which you can build upon.

Daru wrote:

General tip:To get better at drawing anime, stop drawing anime.

It's derived from realism in that it's a stylized representation of what we see in real life. It breaks a few rules to accommodate this stylization which is what results in the unique visual appearance of anime. However, one must first know the rules in order to break them, and the study of realism will lay a sound foundation from which you can build upon.